I choose languages based on what is best suited for the project. That is determined by the architecture of the project (is it a SPA or a more Ye Olde Fashioned

I choose languages based on what is best suited for the project. That is determined by the architecture of the project (is it a SPA or a more Ye Olde Fashioned web site? Is it just an API? Does it need web sockets? etc.) The architecture is dependent on the requirements. Who will maintain this once I'm done writing it counts as a requirement. If I'm making it for someone else and I won't be maintaining it, and they don't have someone on hand to maintain it, I might not want to write it in Clojure or Node because it might be harder for them to find someone who can work on it affordably than if I write it in PHP or Ruby. Sometimes multiple languages will be equally suited to the same type of project, in that case I go with personal preference. But that's very rare. Usually there's some good objective criteria like those listed above which will help you nail it down.